I put on a set of new Edelbrock aluminum heads 50K miles ago and for the last 10K miles I've had problems with oil fouling of plug 3 & 7. I tore down the heads last week and found severe wear on both the valve stems and guides on all cylinders. At the worst spot the valves had 0.004" wear. Add in another 3-4 thou in the guides for a total of 7-8 thou worth of wear!

Just got the heads back from the shop. He had to replace every single valve and guide. The machinist suspected incorrect pushrod length so I checked it today.

As much as I try, I always come up with the intake pushrods being right on and the exhaust is about 0.060-0.070 short. With the intake pushrods being correct I can't for the life of me figure out why there was so much wear on the intakes???

What else can cause accelerated wear on stems & guides? The rest of the valve train looks great. No wear on the roller cam, lifters, pushrods or rockers.

The engine is a 454. Comp hydraulic roller, comp roller tip rockers. 10W-30 mobil 1 oil and makes 40 PSI hot idle, 70 PSI at higher rpm. The engine was perfectly clean inside with no hint of sludge. Spring pressures are reasonable. 140 seat, 340 open.

Side loading the valves from incorrect geometry will damage guides too in short order. Also, when they were assmbled what kind of lube did they have on the stems/guides? What kind of seals are you using?

z,
I just finished a set of those heads myself. Same deal, all the guides were "killed". I dont know the mileage on these. They were off a 302 Ford.

Side loading the valves from incorrect geometry will damage guides too in short order. Also, when they were assmbled what kind of lube did they have on the stems/guides? What kind of seals are you using?

They were straight from Edelbrock at the time so whatever assembly lube Edelbrock uses. The seals are also stock edelbrock which is a viton positive seal.

I noticed the contact patch on the stem is fairly wide. Do you think the cam has too much lift for roller tip rockers and I need to go to a full roller? The cam has 0.573/0.585 lift. I'll try and take a pic of the stem and post shortly.

http://www.imagesup.com/usr/84/geometry.jpg

Here's the contact patch. Seems wide to me? Do I need to replace the roller tip rockers with full rollers?

I think its like Steve said, incorrect geometry ie; possible issues with pushrod length.
Check the contact point at mid lift on # 1 intake and exhaust to rule this out!
Good luck.

Man,you beat me to the post!
That contact area looks good.
Is there an issue with the guide plates binding?

Is there an issue with the guide plates binding?

No witness marks on the pushrods of any undue contact. I would think that would hurt the pushrod more than the valve?

z,
That contact patch looks about as good as you can get it. One thing that a lot of people overlook that will affect guide wear is the valve job itself. If the seats have a lot of runout, the valve will be always trying to move to one side when it closes, and will wear out the guides in no time at all. I know the heads were new, but as much as I hate to say it, with mass production, errors can be made pretty easily.
I cant tell by your picture, but are the springs pretty well secured as far as being able to move around ? That is another thing that I dont like about some of the aftermarket heads, Edelbrock especially. They just put a shim under the spring and there is nothing to locate the spring and keep it from moving around. I refuse to put them back together without a spring locater of some type. I dont know how much it affects guide wear, but it sure cant help it any with the spring able to move all over the place.

Bill: Thanks for the info, it makes me feel much better. I think you may be right about something just being off on the heads from the factory. A few months ago I replaced the stock edelbrock springs (which indeed did NOT have any locators) with new springs that use cups. They are now securely locked in place. The valve seats were redone with the rest of the stuff and I have no doubt it was done right.

Sounds like I just need to bolt it together and get longer pushrods for the exhausts and I'm good.

Those springs look like bee hive springs.

Those springs look like bee hive springs.

Yep. I put them in a few months ago.

I put on a set of new Edelbrock aluminum heads 50K miles ago and for the last 10K miles I've had problems with oil fouling of plug 3 & 7. I tore down the heads last week and found severe wear on both the valve stems and guides on all cylinders. At the worst spot the valves had 0.004" wear. Add in another 3-4 thou in the guides for a total of 7-8 thou worth of wear!

Just got the heads back from the shop. He had to replace every single valve and guide. The machinist suspected incorrect pushrod length so I checked it today.

As much as I try, I always come up with the intake pushrods being right on and the exhaust is about 0.060-0.070 short. With the intake pushrods being correct I can't for the life of me figure out why there was so much wear on the intakes???

What else can cause accelerated wear on stems & guides? The rest of the valve train looks great. No wear on the roller cam, lifters, pushrods or rockers.

The engine is a 454. Comp hydraulic roller, comp roller tip rockers. 10W-30 mobil 1 oil and makes 40 PSI hot idle, 70 PSI at higher rpm. The engine was perfectly clean inside with no hint of sludge. Spring pressures are reasonable. 140 seat, 340 open.The guides where set-up to tight.Maybe the wrong seals not letting enough oil go to the guide.On some of the Teflon seals I have had to trim the very top metal band on the seals for a little extra oil.

After I swapped heads, we pulled 3 valves out of the 781's, exhausts were fine, the one intake we pulled had excessive play and the end of the valves had a pattern just like yours. The heads were supposed to be fresh, new guides and all, not sure what went wrong. Maybe 300 passes at the track and a few street miles, had the old umbrella lookin seals, with a spring around the top? I'm thinking they went on the cheap, not sure if they did the guides at all.

To me, I ain't gonna run NO extreme lift cams b/c lift is a secondary power producer when compared to duration!!

What's the LS- engines doing for the lift/guide wear thing nowadays??

pdq67

Is 50k miles out of a set of performance heads bad? Is it a bronze liner thing?

No wonder I see these heads used on ebay all the time all taken apart.

Z-Did you check the installed hgts and check for coil bind with the new springs.
I have found that the bronze guides tolerate a little less oil as they seem to retain more oil in thier porous design.

Vince: It's not a liner thing as the heads had bronze guides. They have liners now after the rebuild. According to the machinist they will last better than the edelbrock guides. They are the spiral k-lines.

Johnny: Yes, coil bind & installed height was verified by me and again by the machinist. There's also tons of retainer-seal clearance.

To me, I ain't gonna run NO extreme lift cams b/c lift is a secondary power producer when compared to duration!!

What's the LS- engines doing for the lift/guide wear thing nowadays??

pdq67

You're still old school, used to be moderate lift, long duration. Now its high lift, short duration. Where ya been? :D I know, building towtruck motors ;)

I dont know if it would be an issue with the Edelbrock heads, but the GM heads were real bad about the guide bores not being square with the spring seat pockets. The result was the spings were trying the pull the valve straight in a slighty canted guide and causes excessive side load on the guide walls and valve stems.
We always spot face the spring pockets on the BB heads just to be sure they are a true 90 with the guide bores.